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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

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I apologise if this is already common knowledge, but I just found out you can have multiple layers of LUKS encryption on a drive! (lemmy.ml)

submitted 6 months ago by communism@lemmy.ml to c/linux@lemmy.ml

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[Image description:
Screenshot of terminal output:

~ ❯ lsblk
NAME           MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
sda              8:0    1  62.5M  0 disk  
└─topLuks      254:2    0  60.5M  0 crypt 
  └─bottomLuks 254:3    0  44.5M  0 crypt

/end image description]

I had no idea!

If anyone else is curious, it's pretty much what you would expect:

cryptsetup -y -v luksFormat /dev/sda
cryptsetup open /dev/sda topLuks
cryptsetup -y -v luksFormat /dev/mapper/topLuks
cryptsetup open /dev/mapper/topLuks bottomLuks
lsblk

Then you can make a filesystem and mount it:

mkfs.ext4 /dev/mapper/bottomLuks
mount /dev/mapper/bottomLuks ~/mnt/embeddedLuksTest

I've tested putting files on it and then unmounting & re-encrypting it, and the files are indeed still there upon decrypting and re-mounting.

Again, sorry if this is not news to anyone else, but I didn't realise this was possible before, and thought it was very cool when I found it out. Sharing in case other people didn't know and also find it cool :)

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[–] Jawa@lemmy.world 36 points 6 months ago (2 children)

You can also just split the password for a single LUKS into two parts and give one each to the two people :D

[–] hperrin@lemmy.world 9 points 6 months ago

Yeah, you’re right. That’s better.

[–] flashgnash@lemm.ee 1 points 5 months ago (1 children)

But then you know both parts of the password and so must be killed to keep the machine secure

[–] Jawa@lemmy.world 1 points 5 months ago

Ideally you would never have to because you just have the two people come up with their part of the password and then initialise the LUKS partition together. Sorta like a key ceremony